That rationalism also gave spectralism an edge. Many of its sounds were genuinely "beautiful," but beauty had been suspect ever since the end of the first world ar, and by the end of the second, it was basically verboten. But spectralism's extremely scientific approval (replete with mathematical analysis of frequency relations) gave cover to composers entering this sound world. It's a nasty and non-too-secret fact that composer, in their geekiness, get very excited, and indeed feel empowered, by the technical arcana for the field (in fact like most professors, look at doctors, lawyers, engineers, financial managers--why do artists have to be intuitive naifs). Spectralism answered this need with a vengeance. It allowed the French to reassert their intellectual, not just sensual, authority. It was a godsend. And it's not surprising either that like serialism, it has too migrated to the United States, first in the appointment... et seq.